Electric conduit and process of making the same



H. M. SHORT.

ELECTRIC CONDUIT AND PROCESS OF MAKING SAME.

APPHQA'HON FILED FEB. 24, I920.

Patented NOV. 15, 1.921, v

UNITED" STATES HENRY I. SHORT, OI YAN, NEW YORK, ASSIGNOR TO SHORT PATENT oFrlca.

ELECTRICAL MFG.

6031,01 PENN YAN, NEW YORK, A GORPORATION OF NEW YORK.

EIIECTBIC CONDUIT AND PROCESS OF MAKING THE SAME.

Specification of Letters Patent.

Patented Nov. 15, 1921.

Application filed February 24, 1920. Serial No. 860,565.

To all whom it may concern:

Be it known that I, HENRY M. Snorrr, a citizen of the United States of America, residing at Penn Yen, New York, have 1nvented a new and useful Electric Conduit and Process of Making the Same, of which the following is a specification.

My invention relates particularly to a flexible non-metallic type of construction for electric conduits.

he main object is the manufacture of a strong durable waterproof and fireproof construction which can be made economically and which can be readily finished. The invention relates not only to the fin1shed product, but to the method of making 1t.

The finished conduit in its preferred form embodies a continuous lining strip, a ramforcing helix adhering thereto, and an outer textile fabric covering. The lining is pref erably made of a strip of cloth such as a light cambric or heavy muslin gummed on one side. The helix is preferably formed of a twisted paper cord. The coverin is preferably of cotton knitted tightly. hen the parts are assembled, the whole is immersed in a suitable compound to stiffen it and render it waterproof and substantially fire roof or slow burning.

igure 1 is a diagrammatic view illustrating the different steps of forming the conduit.

Fig. 2 is a fragmentary view showing the parts of the finished conduit.

Fig. 3 is a fragmentary longitudinal sectional view on an enlarged scale.

Fig. 4 is a transverse sectional view on an enlarged scale.

The lining 5 is preferably gummed on the outside and formed into a tube over the mandrel 6 preferably with the edges slightly overlapping. The cloth lining strip should have sufficient gum or other substance to make it somewhat stiff sothat it will hold its shape on the mandrel in the process of manufacture.

The cord 7 is wound tightly around the lining while it is on the mandrel. The cord is preferably damp or wet so as to cause it to stick or adhere to the gummed surface of the lining and also so as to stiffen the cord somewhat. It will be obvious that instead of moistening the cord the gummed surface of the lining could be moistened first and the cord wound on in its dry state. This cord may be of any suitable cross sectional shape preferably round.

he outer covering 8 may be formed in an well known manner but is preferably knltted around the cordand the lay of the cord and the knitting are made to correspond so that the loops 8 between the adjacent helices of the cord as indicated in Fig. 3.

After the covering has been formed the conduit is carried through or immersed in a tank or tanks such as 9 containing the de-, sired compound or compounds. This compound 10 soaks through the interstices of the cover1ng and between the coils of the cord when they are spaced apart so as to render the finished article substantially waterproof and fireproof and to stiffen it when cold and hold the parts permanently in their proper relation. Com unds for rendering a condult substantia 1y waterproof and fireproof are well known in the art and need not be specifically described here.

By this construction, although the lining adheres tenaciously to the cord, the conduit is nevertheless sufficiently flexible to pass the required tests. Ordinarily the use of damp or moist cord is sufficient to produce the necessar adherence. The underlying edge of the lining at the overlap may, however, be dampened before forming, if desired, so as to more effectively unite the edges and prevent any possibility of the impregnating compound passing through to the interior of the conduit.

Obviously the interior of the tube may be powdered with soap-stone or other anti-frietion material if desired, and it will lodge in the interstices of the lining. Obviously the exterior of the product may also-be treated with material such as powdered mica as is customary in this art.

*claim:

1. The process of forming an article of the character described which comprises form ng a lining strip having a gummed surface lnto a tube with the gummed surface on the outside, then winding a cord about the tube and Inoistening one of said elements so as to cause the cord to adhere to the lining, then formin a covering about the cord and afterward immersing the parts in a suitable compound and permitting the compound to pass through the covering and between the coils of the cord.

will draw part way down 2. The process of forming an article of the character described which comprises formin a gummed strip of cloth into a tube with the gummed surface on the outside, winding a moist cord on said tube prising a longitudinally extending lining strip, a cord helically wound thereon and with adjacent helices spaced apart from each other, and an outer textile covering knitted about said cord with the loops thereof Sitting between adjacent helices of said cor 5. The process of forming a flexible nonmetallic conduit which comprises forming an inner smooth fabric lining, winding thereon a cord and simultaneously therewith causing said cord to adhere to the outer surface of said lining and then forming a knitted fabric covering around said cord and then immersing said tube in a suitable impregnating compound.

6. A flexible non-metallic conduit comprising a longitudinally extending lining strip of stilfened cloth, a cord helically wound thereon and with adjacent helices spaced apart from each other, an outer textile covering knitted about said cord and lining and a waterproof and fireproof composition applied to said knitted covering and extending through the interstices of the covering and between the helices to the inner lining strip.

7. The process of forming a flexible nonmetallic conduit which consists in forming on a mandrel an inner lining tube of a strip of stiffened cloth, then winding a cord tightly about said formed tube on the mandrel with adjacent coils spaced apart, then knitting a covering tightly about said cord and lining tube on the mandrel, and afterward immersing the conduit parts in a suitable compound and permitting said compound to pass through the interstices of said knitted covering and between the adjacent coils to the inner lining tube.

8. A flexible non-metallic conduit coinprisin a longitudinally extending lining strip lormed into a tube, a cord helically wound thereon and having adjacent helices spaced apart from each other, and outer knitted textile covering inclosing said lining strip and helically wound cord and a Waterproof and fireproof composition applied to said knitted textile coverin and extending through the interstices of said knitted covering and between the helices to the inner lining strip.

9. A flexible non-metallic conduit comprising an inner lining in the form of a tube, an outer covering in the form of a knitted tube surrounding said inner lining tube and a waterproof and fireproof composition applied to said outer knitted covering and passing through the interstices in said covering.

HENRY M. SHORT. 

